The present invention relates to electrical encoders that convert angular or linear mechanical movement or position to a digital electrical output.
Various schemes exist to convert angular or linear mechanical position to a digital output. The simplest converters are potentiometers, which convert position to an output voltage by acting as a resistive divider. The analog output from a potentiometer can then be converted to a digital format, if required. A multiposition switch may be used to generate an output signal that consists of discrete steps.
More recently, digital incremental encoders have emerged to be used with microprocessor based equipment. A typical digital encoder includes one or more tracks and sensors arranged to produce a pair of square wave patterns with a 90-degree phase shift.
Electrical encoders are well known in the art, as exemplified by the rotary encoder described in U.S. Pat. No. 4,599,605 to Froeb et al. Such devices typically include a housing that encloses a substrate having a conductive pattern formed a thereon to define a preselected digital signal, in the form of a pulse train or the like. A rotor, rotated by a shaft, carries a rotating element that electrically interconnects with the conductive pattern as the rotor is rotated to generate an electrical signal having the digital characteristics defined by the conductive pattern on the substrate. For example, the rotor may carry a rotating contact element that mechanically contacts the conductive pattern as the rotor is rotated, to generate the electrical signal. In other encoders, a non-contacting rotor is used. Non-contacting rotors may, for example, be magnetic, optical, or capacitive.
Some encoders convert linear movement into the preselected digital signal using a slider rather than a rotor, as also understood by those skilled in the art.
The present invention converts mechanical movement of a device input into a signal that can be applied to particular purposes. In accordance with the present invention, the encoder and associated signal conditioning and processing circuitry are embedded together as a single unit for simplicity of assembly into particular applications, and for reliability.
The present invention is an integrated digital electronic encoder that includes a substrate with first and second substantially opposed major surfaces, and a digital encoder formed on the first major surface of the substrate. The encoder comprises an actuation shaft, and the encoder is configured to generate electrical signals in response to movement of the actuation shaft. Electronic circuitry is attached to the second major surface of the substrate, preferably using surface mount technology. The electronic circuitry is electrically connected with the digital encoder to process the signals produced by the encoder, and preferably includes programmable logic.